Conventionally, an electrically heated catalyst or electric heating catalyst (hereinafter referred to as “EHC”), in which a catalyst is heated by a heat generating element that generates the heat by applying the electricity, has been developed as an exhaust gas purification catalyst provided for an exhaust gas passage of an internal combustion engine.
In EHC, an insulating member, which provides insulation from electricity, is provided between the heat generating element which generates the heat by applying the electricity and a case which accommodates the heat generating element. For example, Patent Document 1 discloses such a technique for EHC that a mat composed of an insulator or insulating material is provided between a carrier which generates the heat by applying the electricity and a case which accommodates the carrier. The provision of the insulating member as described above makes it possible to suppress any short circuit formation between the heat generating element and the case.
Patent Document 2 discloses a technique concerning a position of installation of a temperature sensor in order to preferably perform the temperature management for a filter and a heater in relation to such an arrangement that an exhaust tube of an internal combustion engine is provided with the filter which collects particulates contained in an exhaust gas and the heater which heats the filter in order to regenerate the filter. Patent Document 2 describes the fact that if a temperature detecting unit of the temperature sensor is installed in the vicinity of the heater, the temperature detection value of the temperature sensor is hardly lowered even when the heater is turned OFF.